405 research outputs found
Neuartige zwitterionische λ5-Spirosilicate: Synthese und Kristallstruktur von Bis[1,2-benzoldiolato(2-)][2-(dimethylammonio)phenyl]silicat sowie Synthese von Bis[2,3-naphthalindiolato(2-)][2-(dimethylammonio)phenyl]silicat-Hemiacetonitril-Solvat
No abstract available
A Binaural Cochlear Implant Sound Coding Strategy Inspired by the Contralateral Medial Olivocochlear Reflex
[EN] Objectives: In natural hearing, cochlear mechanical compression is dynamically adjusted via the efferent medial olivocochlear reflex (MOCR). These adjustments probably help understanding speech in noisy environments and are not available to the users of current cochlear implants (CIs). The aims of the present study are to: (1) present a binaural CI sound processing strategy inspired by the control of cochlear compression provided by the contralateral MOCR in natural hearing; and (2) assess the benefits of the new strategy for understanding speech presented in competition with steady noise with a speech-like spectrum in various spatial configurations of the speech and noise sources.
Design: Pairs of CI sound processors (one per ear) were constructed to mimic or not mimic the effects of the contralateral MOCR on compression. For the nonmimicking condition (standard strategy or STD), the two processors in a pair functioned similarly to standard clinical processors (i.e., with fixed back-end compression and independently of each other). When configured to mimic the effects of the MOCR (MOC strategy), the two processors communicated with each other and the amount of backend compression in a given frequency channel of each processor in the pair decreased/increased dynamically (so that output levels dropped/ increased) with increases/decreases in the output energy from the corresponding
frequency channel in the contralateral processor. Speech reception thresholds in speech-shaped noise were measured for 3 bilateral CI users and 2 single-sided deaf unilateral CI users. Thresholds were compared for the STD and MOC strategies in unilateral and bilateral listening conditions and for three spatial configurations of the speech and noise sources in simulated free-field conditions: speech and noise sources colocated in front of the listener, speech on the left ear with noise in front of the listener, and speech on the left ear with noise on the right ear. In both bilateral and unilateral listening, the electrical stimulus delivered to the test ear(s) was always calculated as if the listeners were wearing bilateral processors.
Results: In both unilateral and bilateral listening conditions, mean speech reception thresholds were comparable with the two strategies for colocated speech and noise sources, but were at least 2 dB lower (better) with the MOC than with the STD strategy for spatially separated speech and noise sources. In unilateral listening conditions, mean thresholds improved with increasing the spatial separation between the speech and noise sources regardless of the strategy but the improvement was significantly greater with the MOC strategy. In bilateral listening conditions, thresholds improved significantly with increasing the speech-noise spatial separation only with the MOC strategy.
Conclusions: The MOC strategy (1) significantly improved the intelligibility of speech presented in competition with a spatially separated noise source, both in unilateral and bilateral listening conditions; (2) produced significant spatial release from masking in bilateral listening conditions, something that did not occur with fixed compression; and (3) enhanced spatial release from masking in unilateral listening conditions. The MOC strategy as implemented here, or a modified version of it, may be usefully applied in CIs and in hearing aids
Influence of imperfections on the photonic insulating and guiding properties of finite Si-inverted opal crystals
Indication for the disappearance of reactor electron antineutrinos in the Double Chooz experiment
The Double Chooz Experiment presents an indication of reactor electron
antineutrino disappearance consistent with neutrino oscillations. A ratio of
0.944 0.016 (stat) 0.040 (syst) observed to predicted events was
obtained in 101 days of running at the Chooz Nuclear Power Plant in France,
with two 4.25 GW reactors. The results were obtained from a single 10
m fiducial volume detector located 1050 m from the two reactor cores. The
reactor antineutrino flux prediction used the Bugey4 measurement as an anchor
point. The deficit can be interpreted as an indication of a non-zero value of
the still unmeasured neutrino mixing parameter \sang. Analyzing both the rate
of the prompt positrons and their energy spectrum we find \sang = 0.086
0.041 (stat) 0.030 (syst), or, at 90% CL, 0.015 \sang 0.16.Comment: 7 pages, 4 figures, (new version after PRL referee's comments
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Endophytic bacterial community composition in wheat (Triticum aestivum) is determined by plant tissue type, developmental stage and soil nutrient availability
Aims: To understand effects of tissue type, growth stage and soil fertilisers on bacterial endophyte communities of winter wheat (Triticum aestivum cv. Hereward).
Methods: Endophytes were isolated from wheat grown under six fertiliser conditions in the long term Broadbalk Experiment at Rothamsted Research, UK. Samples were taken in May and July from root and leaf tissues.
Results: Root and leaf communities differed in abundance and composition of endophytes. Endophytes were most abundant in roots and the Proteobacteria were most prevalent. In contrast, Firmicutes and Actinobacteria, the Gram positive phyla, were most prevalent in the leaves. Both fertiliser treatment and sample time influenced abundance and relative proportions of each phylum and genus in the endosphere. A higher density of endophytes was found in the Nil input treatment plants.
Conclusions: Robust isolation techniques and stringent controls are critical for accurate recovery of endophytes. The plant tissue type, plant growth stage, and soil fertiliser treatment all contribute to the composition of the endophytic bacterial community in wheat. These results should help facilitate targeted development of endophytes for beneficial applications in agriculture
Cell Survival from Chemotherapy Depends on NF-ÎșB Transcriptional Up-Regulation of Coenzyme Q Biosynthesis
9 pages and 6 figures.[Background]
Coenzyme Q (CoQ) is a lipophilic antioxidant that is synthesized by a mitochondrial complex integrated by at least ten nuclear encoded COQ gene products. CoQ increases cell survival under different stress conditions, including mitochondrial DNA (mtDNA) depletion and treatment with cancer drugs such as camptothecin (CPT). We have previously demonstrated that CPT induces CoQ biosynthesis in mammal cells.[Methodology/Principal Findings]
CPT activates NF-ÎșB that binds specifically to two ÎșB binding sites present in the 5âČ-flanking region of the COQ7 gene. This binding is functional and induces both the COQ7 expression and CoQ biosynthesis. The inhibition of NF-ÎșB activation increases cell death and decreases both, CoQ levels and COQ7 expression induced by CPT. In addition, using a cell line expressing very low of NF-ÎșB, we demonstrate that CPT was incapable of enhancing enhance both CoQ biosynthesis and COQ7 expression in these cells.[Conclusions/Significance]
We demonstrate here, for the first time, that a transcriptional mechanism mediated by NF-ÎșB regulates CoQ biosynthesis. This finding contributes new data for the understanding of the regulation of the CoQ biosynthesis pathway.ï»żThis work was supported by spanish Ministerio de Educacion y Ciencia Grant BFU2005-03017.Peer reviewe
Why do banks promise to pay par on demand?
We survey the theories of why banks promise to pay par on demand and examine evidence about
the conditions under which banks have promised to pay the par value of deposits and banknotes on
demand when holding only fractional reserves. The theoretical literature can be broadly divided into four
strands: liquidity provision, asymmetric information, legal restrictions, and a medium of exchange. We
assume that it is not zero cost to make a promise to redeem a liability at par value on demand. If so, then
the conditions in the theories that result in par redemption are possible explanations of why banks
promise to pay par on demand. If the explanation based on customersâ demand for liquidity is correct,
payment of deposits at par will be promised when banks hold assets that are illiquid in the short run. If
the asymmetric-information explanation based on the difficulty of valuing assets is correct, the
marketability of banksâ assets determines whether banks promise to pay par. If the legal restrictions
explanation of par redemption is correct, banks will not promise to pay par if they are not required to do
so. If the transaction explanation is correct, banks will promise to pay par value only if the deposits are
used in transactions. After the survey of the theoretical literature, we examine the history of banking in
several countries in different eras: fourth-century Athens, medieval Italy, Japan, and free banking and
money market mutual funds in the United States. We find that all of the theories can explain some of the
observed banking arrangements, and none explain all of them
Correction:Association of low-frequency and rare coding variants with information processing speed
Ca2+-induced Ca2+ Release in Chinese Hamster Ovary (CHO) Cells Co-expressing Dihydropyridine and Ryanodine Receptors
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